1. Field of the Invention
The present invention relates to apparatus for producing expansion-molded articles. In particular, it relates to apparatus for producing expansion-molded articles capable of producing expansion-molded articles continuously by thermal expansion of synthetic resin foamed and expanded beads (hereinafter to be referred to as xe2x80x9cfoamed beadsxe2x80x9d) and mutually fusion-bonding these foamed beads.
2. Description of the Related Art
As methods of molding foamed beads to a prescribed shape by fusion-bonding these beads by expanding them by heating, there are known a method in which the foamed beads are packed into a metal mold, and molded while heating with steam (hereinbelow, this method of molding is termed a batch molding method), and a method wherein the foamed beads are continuously molded by being passed through a heating region while being fed between upper and lower belts (hereinbelow such a method of molding is termed a continuous molding method). Compared with the batch molding method, the continuous molding method has the advantages that expansion-molded articles (hereinbelow expansion-molded articles may be abbreviated to molded articles) can be manufactured continuously and that molded articles of long dimensions can be obtained; as a method of continuously molding polystyrene resin foamed beads, for example the method disclosed in published Japanese Patent Number Sho. 52-2424 is known. Also, as methods of continuously molding polyolefin resin foamed beads, the methods of Laid-open Japanese Patent publication number Hei. 9-104026, Laid-open Japanese Patent publication number Hei. 9-104027, Laid-open Japanese Patent publication number 2000-6253, Laid-open Japanese Patent publication number 2000-15708 and U.S. Pat. No. 5968430 previously applied for by the present applicants are known.
However, conventional apparatus for manufacturing expansion-molded articles used in the method of continuous molding described above is constructed such that foamed beads are supplied between continuously traveling belts along upper and lower surfaces within a passageway whereof the cross-section defined by the structural members constitutes an approximately rectangular shape, these foamed beads being expanded by heating while they are fed in a heating region and these foamed beads being mutually fusion-bonded; so when it is desired to alter the thickness or width of the expansion-molded article which is to be obtained, it is necessary to replace the belt and/or structural members by ones of different width; i.e. there is the problem that every time the width or thickness of the expansion-molded article that is manufactured is changed, a complicated operation of changing the belt or structural members is necessary, and belts or structural members of a number depending on the differences in width and/or thickness of the molded articles must be provided beforehand, so that the cost of the apparatus is considerable.
In view of the above, an object of the present invention is to provide apparatus for producing expansion-molded articles wherein the thickness and/or width of the molded articles that are to be manufactured can easily be altered.
(Means for Solving the Problem)
Specifically, an apparatus according to the present invention for manufacturing expansion-molded articles comprises a belt that continuously travels along the upper inside face of a passageway, defined by structural members, whose cross-section constitutes an approximately rectangular shape and a belt that continuously travels along the lower inside face thereof, in which foamed beads are continuously molded by successively passing foamed beads supplied between these upper and lower belts through a heating region and cooling region sandwiched between the belts, in which at least one of the upper and lower structural members that form the passageway is constituted so as to be capable of movement in the vertical direction sandwiched between the side-face structural members and comprises means for adjusting the thickness of the expansion-molded article by moving vertically at least one of the upper and lower structural members constituted so as to be capable of movement.
Also, a further apparatus according to the present invention for manufacturing expansion-molded articles comprises a belt that continuously travels along the upper inside face of a passageway, defined by structural members, whose cross-section constitutes an approximately rectangular shape and a belt that continuously travels along the lower inside face thereof, by continuously molding foamed beads by successively passing foamed beads supplied between these upper and lower belts through a heating region and cooling region sandwiched between the belts, in which at least one of the side-face structural members that form the passageway is constituted so as to be capable of movement in the lateral direction sandwiched between the upper and lower structural members and comprises means for adjusting the width of the expansion-molded article by moving in the lateral direction at least one of the side-face structural members constituted so as to be capable of movement.
Preferably the apparatus for manufacturing expansion-molded articles according to the invention comprises sealing means for preventing leakage of heating steam at the location of contact of the movably constituted structural member(s) and the structural members that sandwich the movably constituted structural member(s). According to the present invention, the movably constituted structural member(s) may be supported on a shaft(s) that is/are reciprocated by rotation of a screw(s). Or the movably constituted structural member(s) may be supported by a rod(s) of a cylinder(s).
Preferably the apparatus for manufacturing according to the present invention comprises belts that respectively continuously travel along the inside face of the side-face structural members. Preferably the belts that move along the inside faces of the side-face structural members are provided extending from the commencement of the heating region to the end of the cooling region.
The apparatus for manufacturing according to the present invention embraces apparatus wherein means for adjusting the angle of inclination of the belt on the upper side in the region of supply of the foamed beads are provided on the upper belt. Also it embraces apparatus wherein projections are provided in the vicinity of the inlet of the passageway.